Gramophone sound-box.



No. 637,196. Patented Nov. I4, |899.

E. BERLINER. v

GRAMOPHUNE SOUND BOX.

\Applica.tion led Sept. 17, 1897.;

(No Model.)

Tm: Nonne Pmns ou. mom-umu. wAsnlNnYoN D c UNITED STATES PATENT OFFICE.

EMILE BERLINER, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO THEUNITED STATES GRAMOPHONE COMPANY, OF SAME PLACE.

GRAMOPHONE SOUND-BOX.

SPECIFICATION formrng` part of Letters Patent N O. 637,196, datedNovember 14, 1899. Application filed September 17, 1897. Serial No.651,968. (No model.)

To all whom, z'ft may concern'.-

YBe it known that I, EMILE BERLINER, a citizen of the United States, anda resident of Washington, in the District of Columbia, have inventedcertain new and useful Improvements in Gramophone Sound-Boxes,'of whichthe following is a specification.

This invention has reference to sound-boxes for gramophones, and is animprovement upon the sound-boxes shown and described in my LettersPatent No. 534,543, granted February 19, 1895.

In gramophones the sound-record -is produced in the form of a sinuousline of even depth, usually arranged spirally upon a flat disk ofsuitable material. The receiving or reproducing diaphragm is placed atright angles to the face of the disk, so as to vibrate in a planeparallel to the disk. The vibrations or waves to be recorded orreproduced are transmitted from the diaphragm to the disk, or viceversa, by means of a lever carried by the sound-box and carrying at oneend a stylus engaging the disk. This lever may be of the second order,as in the patent above referred to, or it may be of the first order, asin the present invention; but whatever its form, the vibrations, due tosounds to be recorded or reproduced, are transmitted between thediaphragm and disk by means of the lever.

In the present improvement I use a lever of the first order, since Ifind, among other things, that it is possible by properly proportioningthe leverage to considerably amplify the sounds, especially when thesound-box is designed for reproduction. Ihave also found that a lever ofthe first order Inust be xed at the inner end securely to the diaphragm,so that there may be no lost motion, and itis mainly to this connectionbetween the styluscarrying lever and the diaphragm that the presentinvention is directed. This connection between the inner end of thelever and the diaphragm is of vital importance, since the lever inmoving about its pivot travels through an arc at the point where it isconnected to the diaphragm, and if this connection be a rigid one thediaphragm is put under a strain, due to the apparent shortening of thelever, except at the instant when it is parallel to the diaphragm. ThisI have found to be detrimental to the clear and sharp recording orreproduction of sound. I have overcome this objectionable feature bymaking the connection between the lever and the diaphragm flexible inthe direction of the length of 'the lever, whereby the apparentshortening of the said lever is neutralized. At the same time thisconnection must be rigidly secured to the diaphragm and lever and mustalso be rigid in the plane of vibration of the lever, so that there maybe no lost motion. Such a connectionI have produced by .making it in theform of a flat spring constituting an integral part of the lever, andthe free end of this spring I securely cement or otherwise attach to thediaphragm. It is also necessary that the lever should have a fulcrumwhich permits a free and unrestrained movement of the lever. A fulcrumof the blade-spring type with a normal bias would tend to hold the leverin a given position and to return it to that position when movedtherefrom. This would distort the motion of the diaphragm and interferewith perfect sound recording or reproduction. The diaphragm is thusrelieved from all strain and is thereby made more responsive to delicatevibrations, whereby a more faithful record of sound or reproduction ofrecorded sound is obtained.

This improvement and other related improvements in sound-boxes are fullyset forth in the following detail description with reference to theaccompanying drawings, forming part of this specification, in which-Figure l is a central section of the soundboX. Fig. 2 is a top planView. Fig. 3 is a side elevation, with the lever or stylus-carrier insection on the line w of Fig. 1. Fig. 4 is a perspective view of thelever or styluscarrier. Fig. 5 is a perspective view of a modified formof the top pla'te of the soundboX. Figs. G and 7 are views of thepivotsupport for the lever or stylus-carrier, and Fig. Sis a View of amodified form of the said pivot-support.

Referring to the drawings, there is shown a sound-box body composed of aflat circular head l, with-a peripheral ledge 2 on one face IOO and aneck 3 projecting centrally from the other face. A central openingthrough the head and neck forms the passage for the sound-waves. Theneck and ledge maybe formed in one piece with the head or either or bothmay be separately formed and secured to the said head. A diaphragm 4, ofmica, metal, or other material and of such size as to easily [it insidethe ledge, is carried by the head, but is held from direct contacttherewith by an elastic ring 5, of rubber, felt, or other material.Another similar ring 6 is placed upon the diaphragm, and the wholeisiirmly clamped in place in the shallow chamberor recess formed by theledge 2 by means of a top plate 7, secured by screws or otherwise to theledge. The top plate has a small central perforation 8 for the passageof a connection between the lever or stylus-carrier and the diaphragm.

The stylus-carrier is composed of a lever 9, formed of a iiat piece ofmetal tapering toward one end and set edgewise relative to thediaphragm, with its plane of vibration at right angles to the diaphragm,so as to be as stiff as possible in that direction. Near its wide endthe leveris provided witha double-pointed pivot-pin 10 and is passedthrough thc lever and soldered or otherwise secured to it. Thispivot-pin is grasped by the upturned prongs 1l of a U -shaped yoke-piece12, secured to the ledge 2 by a screw, as shown, or otherwise, the topplate 7 being notched or cut away at one edge to fit around thisyoke-piece. The two upturned prongs 1l of the yoke-piece have each aconical seat 13 for the corresponding pointed or tapered end of thepivot-pin. In order to hold the pivot iirmly against rattling and at thesame time allow freedom of movement on its axis, one or both of theprongs 11 have a normal slight inward spring, so as to grasp the pivotwith the requisite degree of pressure.

The fulcrum which I employhas no bias or trend to return the lever to agiven normal position. I therefore designate it as a nonbiased fulcrum.This is especially important when the spring construction between theend of the lever and the diaphragm is considered.

The inward spring of the prongs 11 of the yoke-piece 12 is shownsomewhat exaggerated in Fig. 6, and the position assumed by the prongswhen the pivot is in place is indicated in Fig. 7.

The stylus-lever carries at its wide or outer end a binding-post orclamp 14, which is arranged to receive a stylus 15, shown in thedrawings as a simple needle-point, which is the form used when thesound-boxis employed for the reproduction of recorded sounds. Thethumb-screw of the binding-post or clamp and the perforation for theinsertion of the stylus are at one side of the center of the body of thebinding-post, so as to provide room for securing the binding-post to thestylus-lever in the mannershown. The body of the binding-post is slit,as shown at 16, and in this slit the end of the stylus-lever is placed,and the binding-post is then soldered or otherwise secured to the lever.

The narrow or inner end of the stylus-lever is twisted a quarter-turn,as shown at 17, and terminates in a portion 18, bent at right angles tothe main portion of the lever and extending in the plane of vibration ofthe latter. The portion 18 serves as the connection between the leverand diaphragm, being secured to the latter by a drop of wax, pitch, orthe like when a mica diaphragm is used or by a drop of solder orotherwise when a metal diaphragm is used. This cementiug orsolderingmaterial is indicated at 19. The connection 1S is here shown asan integral part of the leverand is secured as firmly as possible to thediaphragm, so that there may be no lost motion to injuriously modify thesoundwaves. It is, however, clear that the flexible connection betweenthe diaphragm and the lever or stylus-carrier proper need notnece'ssarily be integral with the latter; but in that case it must berigidly secured to it in any suitable manner.

It will be understood that the stylus-lever is vibrated around itspivot, and consequently the inner end of the stylus lever moves throughan are commensurate with the amplitude of said vibrations. Ashereinbefore stated, I have found that though the arc described by theinner end of the stylus-lever is minute, still the relation between thelever vibrating in a curved path and the center of the diaphragmvibrating in a straight path is so changed that unless compensated forit has an injurious effect upon the character of the sound-waves, sincethe diaphragm is put under a strain that does not correspond to the saidsound-waves. For this reason I make the connection 18 for the greaterportion of its length in the form of a thin flexible flat spring, asindicated, so that it will com pensate for the curved path of the innerend of the lever. At the same time this springconnection, beingpractically at right angles to the diaphragm, is stiff enough in thedirection of the plane of vibration to resist any tendency to buckle.

I have shown in Figs. 5 and 8 two ineditications of the pivot-bearingsfor the styluslever. In Fig. 5 the upturned socketed or perforatedprongs 1l are formed by being struck up from the top plate 7, and theyare similar to and perform the same function as those described withreference to Figs. 6 and 7. In Fig. 8 one of the prongs is made heavierthan the other and only one of them has an inward spring. This form willbe used with reproducing sound-boxes, for in the reprodueing-gramophonethe uppermost pivot-support must sustain the greater portion of theweight of the reproducing sound-box and associated parts, as will beevident from an inspection of the aforesaid Letters Patent.

While I have shown and prefer to use the IIO stylus made detachable fromthe lever or stylus-carrier, it is quite clear that the lever and stylusmay be made integral without departing from my invention.

Having now fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

l. In a gramophone sound-box, the combination of a diaphragm, a leverhaving a nonbiased fulcrum, for conveying vibrations to or from arecord-surface, and a spring connection, between the lever anddiaphragm, flexible in the direction of the length of the lever,substantially as described.

2. In a gramophone soundboX,'the combination of a diaphragm, a leverhaving a nonbiased fulcrum, for conveying vibrations to or from arecord-surface, and a connection between the lever and diaphragmconsisting of a spring integral with the lever and flexible in thedirection of the length of the same, substantially as described.

3. A sound-box for gramophones, comprisv EMILE BERLINER.

Witnesses:

HENRY E. COOPER, F. T. CHAFMAN.

